Method of preparing thiotetraphosphates and product thereof



Patented Mar. 17, 1936 PATENT OFFICE METHOD OF PREPARING THIOTETRAPHOS- l PHAT'ES AND PRODUCT THEREOF Augustus H. Fiske, Warren, and Charles S. Bryan,

Providence, R. I., assignors to Rumford Chem- .ical Works, Rumford, R. I.

No Drawing Application December 7, I934,

Serial No. 756,458

10 Claims. Our invention relates particularly to the pro duction of thiotetraphosphates and the product thereof, but'has relation especially to the production of trithiotetraphosphates of the alkali metals.

The object of our invention is to provide a process and product thereof by means of which thio-' tetraphosphates of the alkali metals may be produced. A further object is to carry out the process by the use merely of materials which are inexpensive and readily obtainable in large quantities.

While our invention is capable of embodiment in many different forms; we have described only certain ways of carrying out the same hereinafter.

For example, in carrying outour invention, the equivalent of 2 molecules of phosphorus pentoxide, P205, the same being preferably finely ground, is mixed with the equivalent of 3 molecules of a sulphide of a metal, for instance sodium sulphide, NazS, or what is known commercially as sodium sulphide, or the corresponding salt of potassium or any other metal, preferably also in a fine state of subdivision as a result of having been finely ground. Where commercial compounds areused an allowance will be made, of

course, for the possible impurities present in calsary, a sintering or solidification takes place,

thus obtaining'a material which is hard at thesesame temperatures, of maximum effectiveness and strength which is a physically and chemically homogeneous compound, the product being obtained probably in accordance with'the following equation,

the product being trithiotetraphosphate of sodium, and which is a sodium salt of the tetraphosphoric acid, the constitution of which is given by Roscoe and Schorlemmer in their Treatise on Chemistry, vol. 1, 1905, page 636, and in which three of theoxygen atoms have been substituted by sulphur.

The ordinary commercial sodium sulphide is dark red in color, whereas the resulting sodium trithiotetraphosphate is of a greenish color before fusion and of a glassy colorless appearance when cooled, which is freely soluble in water and, as in the case of thiophosphates generally, gradually gives a slightly milky precipitate of sulphur with a slight evolution of hydrogen sulphide, H23, upon being dissolved in water. However, this slight reaction in the presence of water does not at all interfere with the various uses of the material to which it may be efiectively and advantageously applied. There are'many advan-. tageous uses to which these compounds may be applied, as, for instances,

As a water softener by keeping the alkali earth bases in a soluble condition. v

In laundries as to save soap by combining withthe alkali earth bases in the washing water.

In delimingleather as in the tanning industry.

In dissolving the lime compounds which may occur in soiled textiles.

To prevent deposits of alkali earth salts forming in hot water systems. A

To prevent deposits of alkali earth compounds in steam boilers and their feed lines.

To prevent deposits of alkali earth compounds in automobile water cooling systems.

To prevent'the formation of alkali earth bases as precipitates in the water to be frozen in artificial ice machines. To prevent the formation of alkali earth precipitates on the outside of cans from the cooling water of the canning industry. a

. To prevent streakydyeing in textiles by keeping any alkali earth compounds in a condition of solubility.

Preventing the formation of soap spots on the cloth in dyeing.

To clean cement or brick walls from limedeposits.

As a softener for water in washing living animals or in baths'for human beings.

For cleaning or washing dishes.

For softening water in which anything may be washed and thus saving soap.

Washingrayon, for instance.

scouring wool.

Kier boiling in bleach'eries.

Boiling off silk. I

metal thiotetraphosphate. 55

2. A process which comprises reacting, by mixing and heating together phosphorus pentoxide with sodium sulphide in substantially their theoretical proportions to produce a thiotetraphosphate.

3. A process which comprises reacting, by mixing and heating together phosphorus pentoxide with an alkali metal sulphide in substantially their theoretical proportions to produce an alkali metal trithiotetraphosphate.

4. A process which comprises reacting, by mixing and heating together phosphorus pentoxide with sodium sulphide 'in substantially their theoretical proportions to produce a trithiotetraphosphate.

5. A process which comprises reacting, by mixing and heating together phosphorus pentoxide with an alkali metal sulphide in substantially AUGUSTUS H. FISKE. CHARLES S. BRYAN. 

